"IMM" wrote in message
...

"Andy R" wrote in message
...

"Eno Case" wrote in message
. ..
IMM

I don't see any downside whatsoever from running a shower from a
combi.

Maybe I misunderstand how they work, but I'd been led to believe that
if
the
shower is supplied from the combi, then for the time that the shower
is
in
use, the radiators won't get supplied with water therefore cooling
the
rooms down? (And some showers take longer than others... ;-) )

Very true

But not an issue.

Also, if the shower is in use, and someone does use a hot tap, the
shower
would be affected somehow, even if it is a good thermostatic one?

The shower will almost certainly slow down as you're drawing off the
same
mains as the shower is, whether it cools down or not depends on whether
the
boiler can supply enough hot water to keep the shower and the tap going
at
once, probably not.

1. It will not cool down if it has a pressure equalising valve either: in
the shower mixer, on the mains pipe when t eneters the property or just
before the shower mixer. They are £30 and available in B&Q Warehouse. The
versions that do the whole hosue are 22mm and more expensive.

2. It will not cool down if the combi is powerful enough.

If these points are wrong, I'll gladly stand corrected, and be even
more
keen to get a thermostatic shower!

You're not wrong but I'd still say go for the shower off the combi, it's
far
far better.

I suppose there's also the issue of not having a backup hot water
supply
(like an electric shower could give me) if the combi boiler breaks
down,
but
that's not a big worry to me.

It would be in the middle of winter in a freezing cold house with no hot
water other than what you can boil in a kettle.

See my post on this point.

FWIW I had a combi installed a year or so ago, reasonably happy but
wouldn't
even consider it again unless I had a decent (22mm at least) incoming
water
main with decent pressure/flow rate.

Well uprate the supply. What is the problems anyway. I find that many
have
decent flow and pressure, but the system is not piped up correctly or
pressure equalizing valves are not used.


We've sold the house now so the prob's disappeared but running 100ft of new
water pipe to the road would be enough to put me off a combi if I did the
project again. We had a Baxi 105e and a 15mm incoming main with a decent
flow rate for that size pipe, however, I'm not convinced you can get enough
water through a 15mm pipe for a house where there is more than one person
using the water at once. You can compromise and fit restrictors then have
kitchen sinks that take forever to fill up if someone's having a shower or
lavatory cisterns that take so long to fill you're embarrassed to let guests
use the loo after you. IMHO if you're in a house that's got any more than
two people living in it and you must have a combi then you need two of them
(or a thermal store or something) and a 22mm or more incoming main.

Rgds

Andy R